Emission regulations for internal combustion engines have tightened over recent years, and the trend is even tightening. For example, regulated emissions of NOx and particles from internal combustion engines, are becoming so low that the target emissions levels are hard to be met. Therefore, aftertreatment systems are used in engines to reduce emissions. For reducing NOx emissions, NOx reduction catalysts, including selective catalytic reduction (SCR) systems, are utilized to convert NOx (NO and NO2) to N2 and other compounds, SCR systems utilize a reactant, such as ammonia, to reduce the NOx.
Simultaneously with the emission regulation demands, also power and efficiency demands for engines increase. On top of that the internal combustion engines should be designed and manufactured with smaller size and decreased weight, if possible.
A solution is needed for cost-efficiently providing an aftertreatment system of exhaust gas for internal combustion engine to reduce emissions capable of fulfilling the requirements for emission regulations without sacrificing too much power and efficiency of the engine and do all this in compact size.